xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

btrfs: Fix wild memory access in compression level parser

Browse Source 
[BUG]
Kernel panic when mounting with "-o compress" mount option.
KASAN will report like:
------
==================================================================
BUG: KASAN: wild-memory-access in strncmp+0x31/0xc0
Read of size 1 at addr d86735fce994f800 by task mount/662
...
Call Trace:
 dump_stack+0xe3/0x175
 kasan_report+0x163/0x370
 __asan_load1+0x47/0x50
 strncmp+0x31/0xc0
 btrfs_compress_str2level+0x20/0x70 [btrfs]
 btrfs_parse_options+0xff4/0x1870 [btrfs]
 open_ctree+0x2679/0x49f0 [btrfs]
 btrfs_mount+0x1b7f/0x1d30 [btrfs]
 mount_fs+0x49/0x190
 vfs_kern_mount.part.29+0xba/0x280
 vfs_kern_mount+0x13/0x20
 btrfs_mount+0x31e/0x1d30 [btrfs]
 mount_fs+0x49/0x190
 vfs_kern_mount.part.29+0xba/0x280
 do_mount+0xaad/0x1a00
 SyS_mount+0x98/0xe0
 entry_SYSCALL_64_fastpath+0x1f/0xbe
------

[Cause]
For 'compress' and 'compress_force' options, its token doesn't expect
any parameter so its args[0] contains uninitialized data.
Accessing args[0] will cause above wild memory access.

[Fix]
For Opt_compress and Opt_compress_force, set compression level to
the default.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ set the default in advance ]
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo
2017-11-06 10:43:18 +08:00
committed by David Sterba
parent b77000ed55
commit eae8d82529
3 changed files with 14 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
fs/btrfs/compression.c
View File

@@ -1529,5 +1529,5 @@ unsigned int btrfs_compress_str2level(const char *str)
if (str[4] == ':' && '1' <= str[5] && str[5] <= '9' && str[6] == 0)
return str[5] - '0';
return 0;
return BTRFS_ZLIB_DEFAULT_LEVEL;
}